A study of the receptive fields of ganglion cells in the cat has been made. Using strong chromatic adaptation, the extent and character of the receptive fields of the several spectral components converging on the ganglion cells has been examined. Central responding areas appear to be well defined. The peripheral areas are not well defined. The spectral component are additive (non-opponent) in the center and in the surround, except for the blue component which does not show opponency; rather, it shows one value, either excitation or inhibition in the center and surround.